Macrocystic serous cystadenoma of the pancreas: importance of co-existent tiny cysts depicted by EUS

The case of a 38-year-old man with an unusual type of serous cystadenoma of the pancreas is reported. A multilocular cystic tumor in the head of the p ancreas was detected on abdominal ultrasonography and computed tomography. On endoscopic ultrasonography, the major cysts ranged from 2.0 to 4.5cm in size. In addition to these large cysts, a few small cysts were detected. Ba sed on these findings, this tumor was diagnosed as a macrocystic type serou s cystadenoma. Because endoscopic retrograde pancreatogram showed a compres sion of the main pancreatic duct around the tumor, and because the size of the tumor had been increasing over a 3-year period, surgical intervention w as performed. The resected tumor consisted of macrocysts, with a few small cysts, and was histologically diagnosed as serous cystadenoma. Endoscopic u ltrasonography appears to provide an excellent inside image of this unusual tumor, and because of its ability to detect small cystic lesions clearly, it could be useful in the diagnosis of macrocystic serous cystadenoma.